XCA is an interface
for managing RSA and DSA keys, certificates,
certificate signing requests, revocation lists and
templates. It uses the OpenSSL and Qt4 libraries.
Certificates and requests can be created and
signed and many x509v3 extensions can be added.
XCA supports multiple root and intermediate
Certificate authorities. The CAs can be used to
create CRLs and extend certificates. The following
file-formats are supported: PEM, DER, PKCS#7,
PKCS#8, PKCS#10, PKCS#12, and SPKAC.

EncFS is an encrypted pass-through filesystem
which runs in userspace on Linux (using the FUSE
kernel module). Similar in design to CFS and other
pass-through filesystems, all data is encrypted
and stored in the underlying filesystem. Unlike
loopback filesystems, there is no predetermined or
pre-allocated filesystem size.

Secluded Notes is a simple text editor that keeps each document as a part of its own executable. That part is called an "attachment", and the program encrypts/decrypts it on the fly with an AES 128-bit cipher. As long as you close the application, it automatically updates itself for the next run.

Cardpeek is a tool to read the contents of ISO7816 smartcards. It features a GUI to represent card data in a tree view, and it is extendable with a scripting language (LUA). The goal of this project is to allow smartcard owners to be better informed about what type of personal information is stored in these devices. The tool currently reads the contents of: EMV bank cards, Calypso public transport cards (such as Navigo, RavKav, and Mobib), Belgian eID cards, GSM SIM cards, the French Vitale 2 health card, some Mifare cards, and Moneo electronic purse cards.

AS2Secure is a PHP library that allows you to send and receive AS2 (Applicability Statement 2) messages from partners. The project is split into two parts: a client to send one or more documents to a partner and a server to receive one or more documents from a partner. Its main features are asyncronous and syncronous MDN, partner setup, digital signatures, message encryption, secure transport (using OpenSSL), support for SSL client authentication, and multiple attachments (AS2 1.2).

sxmppd is a server for the XMPP (Jabber) chat protocol. While other, functional XMPP servers exist, they are not as simple or have many dependencies. It supports user authentication, SSL, roster management,
presence updates and subscriptions, messaging (local users), group chat, and file-based server configuration.

Bitcoin is a peer-to-peer electronic cash system that is completely decentralized, without the need for a central server or trusted parties. Users hold the crypto keys to their own money and transact directly with each other, with the help of a P2P network to check for double-spending.